This proposal seeks support jointly for the 2016 Photosensory Receptors & Signal Transduction Gordon Research Conference (GRC) and associated Gordon Research Seminar (GRS), to be held January in 23-29, 2016 at Hotel Galvez in Galveston, Texas and in the spring of 2018, most likely in April at the GRC site Renaissance Tuscany Il Ciocco Resort, Lucca, Italy. This biennial meeting is one of the most prestigious forums for participants to discuss topics at the frontiers of photobiological and biomedical research. Since it began 15 years ago, this GRC series has regularly brought together leading researchers and developing scientists from across the world. About half of the participants will be from the USA and half from Europe, Asia, Oceania and South America, reflecting the active international community in this scientific area. The 2016 and 2018 conferences will continue to provide a unique platform to unite researchers from a diverse range of subfields and disciplines to discuss and share new results and emerging approaches on natural and synthetic photosensory systems. Although photobiology largely originated in the plant sciences and is still strongly represented there, it now embraces a multitude of other experimental organisms such as bacteria, fungi and mammals. Researchers working on fundamental aspects of hot sensory biology will be united with those focused on developing new technologies in the applied field known as optogenetics. This fast-moving field spans the range from molecular to clinical, with practitioners developing methodologies aimed at directing gene expression, modifying the transmission of nerve impulses and restoring vision. A key to extending such tools is harnessing the diversity of photoreceptor systems that are available in nature. The continued efforts of this GRC/GRS series will ensure that the breadth of these disciplinary interactions is maintained and further developed through vigorous discussion and collaboration. Other unique features of this conference include: a 2:1 (talk versus discussion) time for oral presentations; the sheltered meeting venues where participants dine and socialize together outside of the sessions, afternoon social activities planned to promote networking, and poster displays accessible throughout the day and following evening sessions to maximize exposure, as well as space reserved within the main GRC program for short oral presentations to promote talented graduate students, postdoctoral fellows, and junior faculty poster presentations. The closely associated GRS will also allow students and postdoctoral researchers to bring forth their latest developments in the field, lay the scientific groundwork in areas these junior scientists may be less familiar with, and offer explicit mentoring led by senior scientists in informal, round-table discussions aimed at broad aspects of career development. In each case, the breadth of topics and the diversity of techniques employed in this highly multidisciplinary field will attract a diverse group of scientists with a common interest in photosensory function and application.